need replacement that has outdoor dew point

[raylo]

After many years of service my Lacrosse WS-9118 died and I need a replacement.  But I can't find one that can simultaneously display outdoor temp and dewpoint like my 9118.  Looks like all of the newer models display outdoor RH which really is a useless measurement. I did see one model made by Ambient (1171) that has outdoor dewpoint but toggles that with outdoor temp so to get the dewpoint you lose the outdoor temp (it incomprehensibly displays outdoor RH and dewpoint at the same time).

I see that many of the "professional" weather stations have dew point but I have no need or place to mount the anemometers and such that go along with those.

It looks like I can still get a 9118 from Amazon.  Is that my best (or only?) choice to get simultaneous display of outdoor dewpoint and temp?

[DaculaWeather]

The dew point is just a calculation, are you talking about what or how it displays on a console?

[raylo]

Depends on how you look at it... more accurately RH is calculated from dew point and temp.  My 9118 toggles the display between RH and dewpoint.  I prefer to leave it on dewpoint.  Most current models do not do this, only displaying RH.

The dew point is just a calculation, are you talking about what or how it displays on a console?

[DaculaWeather]

Dew point is calculated based on temperature and humidity. You can take dew point and temp and work backwards but that's not how your weather station calculates it.

http://en.wikipedia.org/wiki/Dew_point

[raylo]

We can argue semantics all day.  You can take wet bulb and dry bulb temps and calculate what you want.  But outdoor RH is a relatively useless number.  If I had a nickel for every time I heard someone say it is 90 degrees and 90% humidity, I'd be a rich man.  Conversely, if I had $1,000,000 for every time it was actually 90 degrees and 90% humidity, I'd have just as much $ I do now... which isn't much.  It just doesn't happen.

Typical RH on a very humid day here is ~100% in the early AM and 45-60% (65-76 degree dew point) in the middle of a very hot day.  In between those extremes RH varies as temp rises.  Much easier to know just how nasty it will be if you know the dew point.

But the question at hand is simple... I just want a replacement device that does what I need, that is display outdoor dew point, without stepping up to a full blown weather station.  Appreciate any input on that....

[raylo]

I know you guys mean well but this is a lot of non-help.  I already know how to calculate between RH and dewpoint and vice versa.  I just want another station that actually **displays** dewpoint (which it knows since it knows RH) so I **don't need** to calculate it or guestimate it.

Dewpoint is much more useful than RH.  Consider the example below. Say you only get to look at your weather station once each day and assuming both days are to get to the same high temp of 90 degrees, which will be the more uncomfortable... and by how much?  I don't think many of you can answer this w/o calculating heat inex or dew point.  On the other hand I can look at my weather station (well, I could until it broke) and read the dewpoint directly and pretty much have the answer, barring a major change in air mass later that day.

Mon, 8:00 AM, 70 degrees 90% RH

Tues, 10:00 AM, 80 degrees 70% RH

[Bushman]

I believe the Oregon WMR200 series display dew point.

[DaculaWeather]

That was my first question...

Since you're having to upgrade, get a Davis.

[VaJim]

take a look here:

http://www.rainwise.com/


 

[raylo]

Thanks for the suggestions guys.  I'd be all over one of those full blown setups with anemometer, rain, Internet connex, etc. but I live in a very tall townhouse so no way to get on the roof (and then have to install a pole there).  I'm too old to be going up a 30' ladder.  I guess I'll go try to get another Lacrosse 9118 that seems to be available even though it is an obsolete model.  This is it here although in the pic it shows outdoor RH being displayed.  But you can toggle that to show dewpoint.  Too $$ for what it does but it looks like it's maybe the only consumer level station that does what I want.

http://www.amazon.com/La-Crosse-Technology-WS-9118U-Wireless/dp/B000BPMS36

[raylo]

I did look into that Ambient one (see my original post) and it is oh so close.  But one of the product reviews I read said that dewpoint toggles with outdoor temp so you can't have a display that shows those together which is exactly what I want.  So you see dewpoint and RH together, which is useless for someone that understands what dewpoint is and understands that you don't need outdoor RH for anything.

Also, I believe that Amazon posting showing the Lacrosse 9118 being available is in error.  I don't believe they actually have it.

Lacrosse does seem to have one model that shows dewpoint but near as I can tell from the manual it is "on demand" by pushing a button rather than a persistent part of the display.  That is silly, too, if true.  I have sent them an e-mail question about that.  That model is:

http://www.lacrosseweatherandmore.com/IVG2/Y/ProductID-80589-.htm

[DanS]

Celestron's 47009 appears to have temp, dew point, and humidity all displayed simultaneously.
You could just leave the wind sensors off or installed at ground level.

Acu-rite's 01015 appears to be able to display temp and dew point together as well.

[raylo]

Thanks Dan.  AccuRite apparently has all remotes sensors (including wind) in one big housing.  That won't work.  I want the small temp/hygro sensor to be separate.  Not sure if the Celestron has separates or not... but so much screen is devoted to wind which I wouldn't use.

I did find these that have dew point but strangely they all are the type that need external power for their color displays. Damn it all, I just want one with the typical battery powered LCD.  I remain baffled that the many units from multiple mfgs that display RH don't have a simple feature to toggle to dew point like my old Lacrosse unit.

http://www.celestron.com/science_education/weather-stations/celestron-4-color-lcd-weather-station.html

http://www.lacrossetechnology.com/308A-805/

http://www.lacrossetechnology.com/450/index.php

[raylo]

Well, I broke down and got this one.  A little more $ than I wanted to spend but it can toggle dew point with outdoor RH, LCD display, not too much screen real estate used for wind, etc...  I just won't use the wind sensor.

http://www.amazon.com/Oregon-Scientific-WMR88A-Semi-Pro-Weather/dp/B004LZLXN8

[raylo]

Got my WMR88A today and I am disappointed.  Got the base unit and temp/hygro units set up quickly enough... scrolled over to the RH display and toggled to dewpoint...  dewpoint displayed promptly and agreed pretty close with wx reports for the area.  But the display reverted to RH after 5 seconds or so!  What??!!

I had read the manual online before I bought this POS and it simply said that one could toggle between RH and dewpoint with the mode button.  NOTHING about automatically reverting to RH.  I don't care how else it performs it's getting a 2 star rating from me based on this one issue alone.

I hereby give up in my quest to find one basic weather station that does what I want.  It seems the RH idiocy has completely captured this market and I just need to realize that resistance is futile and let myself be assimilated.

[raylo]

I'd shave my head and practice a British accent if that would help me get assimilated that way! 

...I hear that "7-of-9" is a wild date, but only if your name is Pickard and you're Captain of a space ship (wink,wink).


...re: being "assimilated."

[mackbig]

Raylo
If you can return it now, I would go for it.  Doesnt sounds like it meets your DP standards.  Since you have strong feelings about how DP is derived, this unit and all other consumer stations (basic to semi-pro to pro) are calculating dp from their RH sensor.   OS RH sensors are notorious for failing rather quickly, year or two max probably, if you make it a year.

Andrew

[raylo]

My issue isn't with how DP is derived, I just want it to be *displayed* persistently.  One glance at the DP in the morning tells me all I need to know about the day ahead barring any major changes in airmass.  One glance at RH in the morning tells me almost nothing since I don't have the table in my head that can translate that to conditions later in the day.

I probably won't return this thing, primarily because I haven't found a unit out there that can actually display DP persistently.  The Lacrosse customer service rep gave me a phone number and web link to a wx station outlet store.  She said they often had more stuff around than they listed so maybe I'll call them to see if they have an old 9118 around.

Raylo
If you can return it now, I would go for it.  Doesnt sounds like it meets your DP standards.  Since you have strong feelings about how DP is derived, this unit and all other consumer stations (basic to semi-pro to pro) are calculating dp from their RH sensor.   OS RH sensors are notorious for failing rather quickly, year or two max probably, if you make it a year.

Andrew

[SlowModem]

The Lacrosse customer service rep gave me a phone number and web link to a wx station outlet store.  She said they often had more stuff around than they listed so maybe I'll call them to see if they have an old 9118 around.

http://www.greatbigoutlet.com    ?   That's the Lacrosse surplus store that I know of.  I have dealt with them before and they're ok (for what they have).

[DanS]

These folks are very friendly and may be helpful as well.

[Speed]

raylo,
I'm in the same boat as you. I had an Oregon Scientific WMR100 as my first weather station but it only lasted a little over a year. I live in southern Louisiana, so dew point is more important to me than RH (I also agree RH is pretty useless as far as comfort goes). I decided to look for a temp/humidity only station that showed outdoor temp and DP at the same time. I can't even remember how many weather stations I looked at, and I even called Ambient Weather asking them if they had any stations that showed outdoor temp and DP at the same time. They said they didn't, though I knew the Vantage Vue did it, so I wasn't sure I could trust that answer. I was like you though, with not needing wind information and I didn't want a big all-in-1 unit and I didn't want to spend as much as the Vue costs. I finally gave up and purchased the Ambient Weather WS-1171. It's nice that you can calibrate the humidity since the readings were not very accurate out of the box, but I still hate having to pick up the console to press buttons (which are hard to press) to show the dew point. I actually wrote one of those reviews for it saying I wish it had what we wanted, but I doubt Ambient will make one that does since their new WS-1173 (the 1171 follow-up) seems to work the same way.

[raylo]

Just checking back about this to see if any mfg has woken up to the fact that dewpoint is far more relevant data than RH and should be available WITH outdoor temp WITHOUT having to press buttons.  As Speed notes the Ambient 1171 and 1173 incomprehensibly toggle DP with temp and not RH.  That just makes no sense.

But it is better than the POS Oregon Scientific I bought.  That requires 2 button presses!  One is to toggle DP with RH (that makes sense at least, except for it times out BACK TO RH after a few seconds) and ANOTHER button press for the backlight just make it readable at all.  What a waste of $ that was.  I should have returned it.

So: Just pulsing the community again to see if anyone makes a basic weather station that:

1. Will persistently display outdoor DP along with outdoor temp
2. Not require an a/c power adapter and use of the backlight button to read the display.

Lacrosse, please bring back the WS-9118!

[Speed]

That's funny that you posted in this thread again. I just took a class this past weekend on weather forecasting and asked the instructor if he thought there was any use for relative humidity. He basically said no, and agreed with me that we should be focusing on dew point; relative humidity just confuses everyone.

[Old Tele man]

That's funny that you posted in this thread again. I just took a class this past weekend on weather forecasting and asked the instructor if he thought there was any use for relative humidity. He basically said no, and agreed with me that we should be focusing on dew point; relative humidity just confuses everyone.

...only to those who don't know what RELATIVE HUMIDITY truly is. Those used to reading a psychrometric chart understand it quite well ("B" and "A" in the graph):



"B" is amount of water in air while "A" is maximum water possible (saturation) in the air; Relative Humidity is the ratio of "what is..." to "what the maximum could be..." based upon vapor pressures.

"E" is dew point (to the left) and commonly grains of water per pound of air (to the right).

"D" is the wet-bulb line; what evaporative coolers work by.

[Scalphunter]

 Think your instructor was way out of the ballpark with his comment. Without relative Humidity you would not be able to calculate your Dewpointat which air is saturate at an then you either have fog or rain.


John